Validation of an imaging based cardiovascular risk score in a Scottish population

Abstract

Objectives A radiological risk score that determines 5-year cardiovascular disease (CVD) risk using routine care CT and patient information readily available to radiologists was previously developed. External validation in a Scottish population was performed to assess the applicability and validity of the risk score in other populations. Methods 2915 subjects aged ≥40 years who underwent routine clinical chest CT scanning for non-cardiovascular diagnostic indications were followed up until first diagnosis of, or death from, CVD. Using a case-cohort approach, all cases and a random sample of 20% of the participant's CT examinations were visually graded for cardiovascular calcifications and cardiac diameter was measured. The radiological risk score was determined using imaging findings, age, gender, and CT indication. Results Performance on 5-year CVD risk prediction was assessed. 384 events occurred in 2124 subjects during a mean follow-up of 4.25 years (0–6.4 years). The risk score demonstrated reasonable performance in the studied population. Calibration showed good agreement between actual and 5-year predicted risk of CVD. The c-statistic was 0.71 (95%CI:0.67-0.75). Conclusions The radiological CVD risk score performed adequately in the Scottish population offering a potential novel strategy for identifying patients at high risk for developing cardiovascular disease using routine care CT data.